Method and apparatus for polishing traveling flat glass



J. H. GRIFFIN April 16, 1940.

Filqd Feb. 3, 1937 illliil'!" Patented Apr. 16 1940 UNITED STATES PATENTOFFICE METHOD AND APPARATUS FOR. POLISHING TRAVELING FLAT GLASSApplication February 3, 1937, Serial No. 123,816 In Great BritainFebruary 5, 1936 12 Claims.

This invention relates to polishing method and apparatus operating topolish both surfaces of traveling flat glass and has for its object aform of polishing apparatus of reduced cost.

In polishing apparatus operating to polish simultaneously both surfacesof a traveling strip of fiat glass, the tools operate in pairs, one ofeach pair on one surface and one opposite to it on the other surface, sothat each serves to support the strip against the pressure exerted bythe other. In the case of tools having an iron operating surfaceemploying an abrasive such as sand with a considerable amount of water,hereinafter termed grinding tools, the strip is cooled by the water andby conduction through the iron operative surface, but in the case of-tools employing a polishing medium such as rouge with a felt or othernon-metallic operative surface (hereinafter termed polishing tools) withwhich only little water can be used, the glass becomes heated to such adegree that it is liable to crack. Undue heating can be avoided byreducing the energy supplied to the polishing tools, but this means thatthe number of tools has to be increased, with consequent increase in thecost of the apparatus.

According to the invention, the polishing tools are in two pluralities,one plurality operating on one side of the strip andtheother on theother side of another portion of the strip, and means are providedopposite each plurality for supporting the strip against the pressureexerted by the tools of-the plurality. The supporting means may be aroller bed or it may be a series of tables, and the tables may slide onor under guides with means for removing a table from the series at theend of each plurality and adding it to the series at the start of thesaid plurality.

It is found that the energy supplied to each tool can be considerablygreater when work is being done on only one side of the strip than whentools operate on both sides opposite to each other. Thereby the numberof tools required is considerably less and the cost of the apparatus,after allowing for the cost of the supporting means, is less.

In the accompanying drawing Figure 1 is a side elevation of a portion ofa grinding and polishing machine, shown diagrammatically in that thesupporting framework and driving gear are omitted Figures 2 and 2a aresimilar views of an alternative constructional form of the in ention,FigureZa being a continuation of Figure 2;

Figure 3 is an end view of Figure 2 from the left, parts being omitted;and

Figure 4 is a section taken on the line 44 of Fig. 2.

Referring to Figure 1, the continuous strip of 6 glass I passes througha plurality of pairs of grinding tools, the two tools of each pairoperating on the 'upper and under sides of the strip respectively, sothat each serves to support the strip against the pressure exercised bythe 10 other; the last pair of grinding tools of the machine is shown at2. The strip is driven through the machine by pairs of driving rollers3. The direction of travel of the strip is from left to right. To theright of the last pair of grinding tools 2, where the strip is shownbroken away,

a suitable length is left free for washing the strip free of sand. Thestrip I then passes under .a roller bed 4, which serves as supportagainst the pressure of the polishing tools 5 operating on the undersideof the strip. The strip then passes over a roller bed 6, which forms asupport against the pressure of the polishing tools I operating on theupper side of the strip. Three polishing tools 5 and three polishingtools I are shown in the drawing, but in practice from twelve to fifteentools are required to operate on each side of the strip. The wholenumber of tools required to operate on one side of the strip may be inone group, followed by a group of those required to operate on the otherside, or the two kinds of tools may be in smaller groups, alternatingone with the other. The rollers I and 6 may be idle rollers or they maybe driven at the speed of travel of the strip. Alternatively, a drivenbelt may be employed as direct support for the strip, the belt passingbetween the strip and the roller beds 4 and 6. The pairs of drivingrollers 3 are then not employed in the polishing section of the machine.4

Referring to Figures 2, 2a and 3, the last pair of grinding tools is notshown, but is to the left of Figure 2. In this form of construction,

a series of tables 8 is employed to support the strip I against thepressure of the polishing tools 5 and I. The tables 8 slide on upperguides 9 in Figure 2 and on lower guides III in Figure 2a. The end viewof a table 8 is seen in Figure 3 in a position above the machine, whilebeing transported. The guides 9 engage the table at the surfaces II.Each table is provided with a rack I2, which is engaged by a pinion I3,shown in dotted lines in Figures 2 and 211. By means of the pinion I3,the series of tables is driven along the guides 9. Each table 8,after-it has a second elevator IT. A table 8 is shown in position in theelevator II at the left hand of Figure 2, and the end view thereof isshown in Figure 3. As seen in this figure, the elevators l5 and I!support the table by rollers l8 engaging it at its edges, the rollers l8being far enough apart to pass over the strip and its supporting rollersl4.

When a table 8 under the guides 9, has reached the position shown at theleft of Figure 2, the elevator I1 is operated to lower another table 8on to the strip. The table then resting on the strip is pushed intocontact with the preceding table under the guides by a pusher l9operated by a pneumatic cylinder or the like 20, and pressure is exertedby the pusher l9 until the rack l2 of the table comes into engagementwith the pinion l3. When the table has passed completely under theguides 9, the elevator I1 is raised to the position shown, where it isready to receive another table from the runway l6.

In Figure 2a, showing the arrangement where the polishing tools Ioperate on the upper side of the strip, the table transporting devicesare similar, though the elevators are of slightly differentconstruction. The elevator 2| receives a table when it is clear of thelast polishing tool and delivers it to the runway 22, which transportsit to the elevator 23, by which it is raised to the level of the strip.The pusher l9 then brings it into contact with the preceding table onthe guides l0.

Alternatively, the tables may be linked together to form an endlesschain, the tables being supported by guides or rollers when supportingthe stripagainst the pressure of the tools.

Having described my invention, I declare that what I claim and desire tosecure by Letters Patent is:

1. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising a plurality of pairs of rollers adapted todrive the strip through the apparatus without reversing the strip facefor face, a plurality of pairs of tools operating with sand and water,the two tools of eachpair operating on the two sides of the strip oneopposite to the other, two groups of tools operating with rouge andwater, arranged respectively on opposite sides of the traveling stripand operatingsimultaneously thereon, one group facing in one directionto operate on the obverse side of the strip and the other group facingin the opposite direction to operate on the reverse side of said strip,the tools of one group being offset with reference to the tools of theother group so as thereby to operate on the traveling strip at differentportions of its length, and non-polishing means arranged directlyopposite each group and adapted to support the strip against thepressure exerted by the tools of the group.

2. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising a plurality of pairs of rollers adapted todrive the strip through the apparatus without reversing the strip facefor face, a plurality of pairs of tools operating with sand and water,the two tools of each pair operating on the two sides of the strip oneopposite to the other, two groups of tools operating with rouge andwater, arranged respectively on opposite sides of the traveling stripand operating simultaneously thereon, one group facing in one directionto operate on the obverse side of the strip and the other group facingin the opposite direction to operate on the reverse side of said strip,the tools of one group being offset with reference to the tools of theother group-so as thereby to operate on the traveling strip at differentportions of its length, and a series of tables arranged directlyopposite each group and adapted to support the strip against thepressure exerted by the tools of the group.

3. Apparatus as in claim 2 comprising guides adapted to support thetables and meansfor removing a table from the series of tables at theend of each group of tables and adding it to the V tools of each pairoperating on the two sides of the strip one opposite to the other, twogroups of tools operating with rouge and water, arranged respectively onopposite sides of the traveling strip and operating simultaneouslythereon, one group facing in one direction to operate on the obverseside of the strip and the other group facing in the opposite directionto operate on the reverse side of said strip, the tools of one groupbeing offset with reference to the tools of the other group so asthereby to operate on the traveling strip at different portions of itslength, and a plurality .of moving supports arranged directly oppositeeach group of tools and adapted to support the strip against thepressure exerted by the tools of the group.

5. Apparatus for polishing a continuousstrip of glass on both sidessimultaneously comprising a plurality of pairs of rollers adapted todrive the strip through the apparatus without reversing the strip facefor face, a plurality of pairs of tools operating with sand and water,the two tools of each pair operating on the two sides of the strip oneopposite to the other, two groups of tools operating with rouge andwater, arranged respectively on opposite sides of the traveling stripand operating simultaneously thereon, one group facing in one directionto operate on the obverse side of the strip and the other group facingin the opposite direction to operate on the reverse side of said strip,the tools of one group being offset with reference to the tools of theother group so as thereby to operate on the traveling strip at differentportions of its length, and a bed arranged directly opposite each groupand adapted to support the strip against the pressure exerted by thetools of the group, the portions of the bed contacting with the stripmoving with the strip.

6. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising means adapted to drive the strip through theapparatus without reversing the strip face for face, a plurality ofpairs of disc tools made of cast iron operating with their flat surfacesin contact with the glass with sand and water, the two tools of eachpair operating on the two sides of the ammo-z strip one opposite to theother, two groups of disc tools covered with a non-metallic materialoperating with their flat surfaces in contact with the glass with rougeand water, arranged respectively on opposite sides of the travelingstrip and operating simultaneously thereon, one group facing in onedirection to operate on the obverse side of the strip and the othergroup facing in the opposite direction to operate on the reverse side ofsaid strip, the tools of one group being offset with reference to thetools of the other group so as thereby to operate on the traveling stripat different portions of its length, and a plurality of moving supportsarranged directly opposite each group of tools and adapted to supportthe strip against the pressure exerted by the tools of the group.

7. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising a plurality of pairs of rollers adapted todrive the strip through the apparatus without reversing the strip facefor face, a plurality of pairs of tools operating with sand and water,the two tools of each pair operating on the two sides of the strip oneopposite to the other and being adapted to conduct away from the glassheat generated during the grinding operation, two groups of toolsoperating with rouge and water, arranged respectively on opposite sidesof the traveling strip and operating I simultaneously thereon, one groupfacing in one direction to operate on the obverse side of the strip andthe other group facing in the opposite direction to operate on thereverse side of said strip, the tools I of one group being. offset withreference to the tools of the other group so as thereby to operate onthe traveling strip at different portions of its length, andnon-polishing means arranged directly opposite each group and adapted tosupport the strip against the pressure exerted by the tools of thegroup.

8. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising a plurality of pairs of rollers adapted todrive the strip through the apparatus without reversing the strip facefor face, a plurality of pairs of tools operating with sand and water,the two tools of each pair operating on the two sides of the strip oneopposite to the other, two groups of tools operating with rouge andwater, arranged respectively on opposite sides of the traveling stripand operating simultaneously thereon, one group facing in one directionto operate on the obverse side of the'strip and the other group facingin the opposite direction to operate on the reverse side of said strip,the tools of one group being oilset with reference to the tools of theother group so as thereby to operate on the traveling strip at differentportions of its length, and a roller bed arranged directly opposite eachgroup and adapted to support the strip against the pressure exerted bythe tools of the group.

9. A method of polishing a continuous strip of glass on both sidessimultaneously while the strip is in motion, characterized in that thesimultaneous polishing operations are effected in offset regions onopposite sides of the strip without' reversing the strip face for face.

10. A method of polishing a continuous strip of glass on both sidessimultaneously while the strip is in motion, characterized in that thesimultaneous polishing operations are effected in offset regions onopposite sides of the strip without reversing the strip face for face,and in that each of said different portions of the strip is supported onthe side opposite directly against the pressure exerted during thepolishing operation.

11. Apparatus for polishing a continuous strip of glass on both sidessimultaneously, comprising a. plurality of pairs of rollers adapted todrive the strip through the apparatus in a horizontal plane, a pluralityof pairs of tools operating with sand and water, the two tools of eachpair operating on the two sides of the strip one opposite to the other,a group of tools operating with rouge and water on the upper surface ofthe strip and non-polishing means engaging the lower surface below thesaid group of tools and adapted to support the strip against thepressure exerted by them, and a second group of tools simultaneouslyoperating with rouge and water on the lower surface of the strip andnon-polishing means engaging the upper surface above the said second Ygroup of tools and adapted to support the strip against the pressureexerted by them.

12-. Apparatus for polishing a continuous strip of glass on both sidessimultaneously comprising means for driving the strip through theapparatus in a horizontal plane, a group of tools operating with rougeand water on the upper surface of the strip and non-polishing meansengaging the lower surface of the strip below said group of tools tosupport the strip against the pressure exerted by said tools, and asecond group of tools simultaneously operating with rouge and water onthe lower surface of the strip and nonpolishing means engaging the uppersurface of the strip above said second group of tools to support thestrip against the pressure exerted by said tools.

JAMES HARRIS GRIFFIN.

